1. Field of the Invention
The present invention relates generally to orthopedic devices and more particularly to ankle braces for stabilizing the ankle against inversion and eversion without limiting normal plantarflexion and dorsiflexion of the ankle and which can be easily fitted to an ankle and worn with a conventional shoe.
2. Description of the Related Art
In the management of certain injuries to the lower extremities such as fractures of the tibia and fibula, malleolar fractures, or severe ankle sprains, it is common to completely immobilize the lower extremity by use of the well-known molded plaster or resin cast.
Once the injured extremity has become stable, however, it has been found that recovery may be effected more rapidly by gradually and progressively permitting the extremity to bear weight and undergo other permitted exercises. Thus, for example, an orthopedic brace such as those disclosed in U.S. Pat. Nos. 4,280,489 and 5,125,400, both of which are assigned to the assignee herein and incorporated herein by reference in their entirety, may be utilized. These braces are pneumatic braces featuring one or more rigid outer shell members having associated therewith an inflatable liner or air cell for engaging a body part or limb. Commercial embodiments of the pneumatic brace incorporating the inventions disclosed in these prior patents are adapted to be fixed about the lower leg and typically comprise an outer shell member, or sidewall, in the form of a U-shaped stirrup having inflatable liners or air cells disposed within the stirrup member in co-extensive relation to the upstanding sidewalls thereof. Strap fastening means maintain the member sidewalls in engagement with confronting portions of the lower leg whereby each air cell serves as a firm supporting cushion of pressurized air between the irregular contours of the lower leg and the member sidewalls.
This brace construction is capable of stabilizing the ankle against eversion and inversion while permitting dorsiflexion and plantarflexion and while being worn inside a conventional shoe. Thus ambulatory functionality and permitted exercises are feasible thereby encouraging more rapid recovery from various injuries to the lower extremity, such as ankle sprains, than otherwise would be possible. The braces are used for ankle sprain management in many countries because of their effectiveness, comfort and convenience in mobilizing yet protecting the ankle from re-injury. They have made xe2x80x9cfunctional managementxe2x80x9d practicable.
The most common ankle injury is a sprain of the anterior talofibular ligament (ATFL) at the anterior margin of the lateral malleolus where swelling and edema originates. Since the ATFL is in the anterior front portion of the ankle, it lies in the uncovered area between the two sides of the stirrup member. To compensate for this uncovered area, many practitioners use a supplemental compression wrap during the initial few days after injury. An elastic ankle wrap is used just for this purpose.
Thus the recovery rate for ankle function following an inversion sprain may be related to the effectiveness of edema control at the injury site. Numerous authors have reported the use of a U-shaped felt or foam rubber device beneath an elastic wrap or adhesive tape for applying focal compression to the soft tissues adjacent to the fibular malleolus. See, for example, Wilkerson et al., xe2x80x9cTreatment of the Inversion Ankle Sprain: Comparison of Different Modes of Compression and Cryo Therapyxe2x80x9d, JOSPT, Volume 17, No. 5, May 1993, pages 240-246. Focal compression consists of pressure application to surface concavities while adjacent proximal convex bony prominences are left uncompressed. See Wilkerson, xe2x80x9cTreatment of the Inversion Ankle Sprain through Synchronous Application of Focal Compression and Coldxe2x80x9d, ATHLETIC TRAINING, JNATA, Volume 26, Fall 1991, pages 220-237. One of the objectives of the studies, as set forth in these articles, was to add focal compression to the uncovered area between the two sides of the stirrup with a pathway up the center of the stirrup for drainage of edema from the area of high pressure to the area of low pressure.
One form of ankle brace that has proved to be particularly effective for control of edema and swelling following a severe sprain is disclosed in U.S. Pat. No. 5,389,065 which is assigned to the assignee herein, the disclosure of which is incorporated by reference in its entirety. Shown and described in the xe2x80x2065 patent is a stirrup-type ankle brace having an outer shell member, the shell member having a lateral elongated, substantially rigid, support member with a corresponding supporting cushion thereon substantially coextensive therewith and an opposed medial support member with a corresponding cushion thereon. The lateral supporting cushion has a pre-inflated flap extending along the anterior margin of its distal end with enough width to cover the area over and surrounding the anterior talofibular ligament. The flap is compressed against the ATF ligament by a strap of elastic hook-and-loop compatible material. A tab of hook material is attached to the anterior end of the elastic strip so that it can engage the opposite end at any length. The strap is retained between the lateral shell and supporting cushion in the preferred embodiment so as to overlap the flap and compress the ATF ligament and medial malleolus when wrapped around the ankle. It does not wrap around either of the shells, but is at the outside surface of the lateral supporting cushion and the inside surface of the medial supporting cushion in the preferred embodiment.
Another form of ankle brace, as disclosed for example in U.S. Pat. Nos. 5,217,431 and 5,330,419, is a boot-type brace. Such braces can effectively be used not only in the rehabilitation phase immediately following the ankle injury, but also during the return to activity phase of the injury, and particularly for use in sports. This brace also has utility as a prophylaxis for healthy ankle joints to prevent new injuries or the recurrence of old injuries during activity. Basically these patents teach a pliant boot that surrounds the ankle joint, as well as the foot and lower leg in the region thereof. The boot may incorporate means of applying compression to the ankle joint. Attached to the boot are a pair of adjustable tension straps vertically disposed about the ankle joint for restricting the mobility thereof. Integral with the boot is a pair of stiffening members positioned about the ankle joint to cooperate with the tension straps in the performance of their mobility restricting function. Further, provided integral with the boot are retention members that isolate the malleoli from the stiffening members for the comfort of the wearer. Finally, one or more retention straps are provided to maintain the stability of the brace.
Other forms of boot-type sport ankle braces are available such as the brace sold under the trade name SPEED BRACE by Royce Medical Company of Camarillo, Calif. and the brace sold under the trade name ASO by Medical Specialties, Inc. of Charlotte, N.C.
A disadvantage of commercially available boot-type ankle braces is that they often inhibit normal plantarflexion and dorsiflexion when worn with conventional shoes, such as athletic shoes, during the activity phase of rehabilitation. Another disadvantage of common boot-type sport ankle braces is that they are typically of top entry construction and have front laces for securely fitting the brace to the foot. These front lacing boots can thus be inconvenient to fit to the ankle and their laces can easily become tangled with the laces of the associated athletic shoe making it difficult for them to be removed when desired.
The present invention improves over the prior art by providing a unitary boot-type ankle brace having the capability of stabilizing an ankle against inversion and eversion without limiting normal plantarflexion and dorsiflexion of the ankle and while simultaneously providing focal compression of the anterior talofibular ligament. The brace is preferably constructed of a flexible material and includes a medial side portion dimensioned and configured to extend along a medial side of a user""s leg and foot, and a lateral side portion dimensioned and configured to extend along a lateral side of the leg and foot. The side portions are joined to a forwardly extending forefoot sleeve portion and to a base portion. In one aspect of the invention the side portions define a rear opening for insertion of the foot, with a strap for selectively connecting the side portions adjacent the user""s heel.
In another aspect of the invention the brace includes a strap dimensioned and configured to extend from a lateral portion of the boot and wrap around a front portion of the boot to a medial side of the boot, the strap passing in close proximity to the anterior talofibular ligament of the user when the boot is applied. The strap thus serves not only as a surrogate anterior talofibular ligament, it also serves to provide focal compression to the ligament to thus promote healing.
In yet another aspect of the invention, both the lateral and medial side portions of the boot are preferably formed with pockets, each containing a relatively rigid shell for limiting inversion and eversion of the ankle. In one preferred form the shells are provided with air cells for conforming them comfortably to the shape of the user""s lower leg and foot.